docs: add custom head

Author: itsjavi

_includes/head-custom.html

@@ -1,7 +1,7 @@
 <style>
     html, body {
         color: #fafafa;
-        background-color: #252525;
+        background-color: #111111;
     }
 
     .markdown-body img {
@@ -12,14 +12,20 @@
     .markdown-body h2, 
     .markdown-body h3, 
     .markdown-body p {
-      border-bottom-color: #555555;
+      border-bottom-color: #333;
     }
 
     .highlight {
       background-color: transparent;
     }
     .markdown-body .highlight pre, .markdown-body pre {
       background-color: #333333;
+      border-radius: 6px;
     }
+
+    a, a:hover {
+      color: #78f7f9;
+    }
+  
 </style>